Oral care compositions

ABSTRACT

Provided are aqueous soluble tin phosphate complexes formed from a mixture comprising tin (II) fluoride and a pyrophosphate salt and oral care compositions comprising the complexes and uses thereof.

This application claims priority to U.S. Provisional Application No. 62/273,314 filed Dec. 30, 2015, which is hereby incorporated by reference in its entirety.

BACKGROUND

Dentinal hypersensitivity is acute, localized tooth pain in response to physical stimulation of the dentine surface by thermal (hot or cold), osmotic, tactile, and/or a combination of thermal, osmotic, and tactile stimulation of the exposed dentin. Exposure of the dentine, which is generally due to recession of the gums, or loss of enamel, frequently leads to hypersensitivity. Dentinal tubules open to the surface have a high correlation with dentinal hypersensitivity. Dentinal tubules lead from the pulp to the cementum. When the surface cementum of the tooth root is eroded, the dentinal tubules become exposed to the external environment. The exposed dentinal tubules provide a pathway for transmission of fluid flow to the pulpal nerves, the transmission induced by changes in temperature, pressure, and ionic gradients.

To relieve dentinal hypersensitivity, dentinal tubules may be plugged. Such occlusion may be carried out either by blocking the tubule with a particle of smaller size than the tubule or by inducing precipitation within the dentin tubule itself.

Tin (II) fluoride (also known as stannous fluoride, SnF₂) has been used in oral care compositions, but has disadvantages. Tin (II) may react with other ingredients of the oral care composition to form insoluble inactive tin compounds, thereby reducing the effective amount of available tin (II) in the composition. In addition, tin (II) fluoride may cause yellow-brown tooth staining and may impart unacceptable astringency to the composition.

While the prior art discloses the use of various oral compositions for the treatment of dentinal hypersensitivity, there is still a need for additional compositions and methods that provide improved performance in such treatments.

BRIEF SUMMARY

Tin (II) fluoride is soluble in water, however, it oxidizes to form insoluble precipitates of tin. In addition, tin can form water insoluble compounds with phosphates.

It has now been discovered that tin (II) fluoride forms an aqueous soluble tin phosphate complex upon mixture with a pyrophosphate salt, e.g., tetrapotassium pyrophosphate (K₄P₂O₇) (TKPP) or tetrasodium pyrophosphate (Na₄P₂O₇) (TSPP). In contrast, tin (II) chloride upon mixture with a pyrophosphate salt, e.g., tetrapotassium pyrophosphate (K₄P₂O₇) (TKPP) or tetrasodium pyrophosphate (Na₄P₂O₇) (TSPP), forms solid (Examples 9 and 10).

When the complex is placed in an oral care composition, the oral care composition, upon use, may provide a precipitate that can plug dentinal tubules, thereby reducing the sensitivity of the teeth. While providing efficient delivery of tin in comparison to compositions with insoluble tin salts, the compositions comprising the tin phosphate complex may not exhibit the instability, tooth staining, and poor taste associated with conventional tin-based oral care products using soluble tin salts.

Provided is an aqueous soluble tin phosphate complex, e.g., formed from a mixture comprising tin (II) fluoride and a pyrophosphate salt, e.g., an alkali pyrophosphate salt, e.g., tetrapotassium pyrophosphate (K₄P₂O₇) (TKPP) or tetrasodium pyrophosphate (Na₄P₂O₇) (TSPP).

Also provided are oral care compositions, e.g., mouthwashes, oral gels, or dentifrices, comprising the aqueous soluble tin phosphate complex. The compositions may be formulated in a suitable oral care composition, e.g., a mouthwash, oral gel, or dentifrice, for example comprising one or more abrasives, surfactants, foaming agents, vitamins, enzymes, humectants, thickeners, antimicrobial agents, whitening agents, pH agents, preservatives, flavorings, and/or colorants.

Further provided are mouthwashes comprising the aqueous soluble tin phosphate complex, which are clear when formulated, but which provide a precipitate when contacted with saliva.

Further provided are methods of using the oral care compositions to reduce or inhibit dentinal hypersensitivity comprising applying the composition to teeth.

Further provided is a method of occluding dentin tubules comprising applying the oral care compositions to teeth.

Further provided are methods of using the oral care compositions to reduce or inhibit one or more of dental caries (i.e., cavities), gingivitis, and plaque comprising applying the composition to teeth.

Further provided are methods of making the aqueous soluble tin phosphate complex comprising combining tin (II) fluoride and a pyrophosphate salt, e.g., an alkali pyrophosphate salt, e.g., tetrapotassium pyrophosphate (K₄P₂O₇) (TKPP) or tetrasodium pyrophosphate (Na₄P₂O₇) (TSPP), in aqueous solution, e.g., at a molar ratio of at least 1P:1Sn, e.g., 1P:1Sn to 15P:1Sn, e.g., 1P:1Sn to less than 15P:1Sn, e.g., 1P:1Sn to 10P:1Sn, e.g., 1P:1Sn to less than 10P:1Sn, e.g., 1P:1Sn to 5P:1Sn, e.g., 1P:1Sn to less than 5P:1Sn, e.g., 1P:1Sn to 2P:1Sn, e.g., 1P:1Sn, e.g., 2P:1Sn, e.g., 5P:1Sn, e.g., 10P:1Sn, e.g., 15P:1Sn; optionally isolating the complex thus formed as a solid.

Further provided are methods of making the oral care compositions comprising admixing the aqueous soluble tin phosphate complex with an oral care base, e.g., a mouthwash, oral gel, or dentifrice base.

Further areas of applicability of the present invention will become apparent from the detailed description provided hereinafter. It should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are intended for purposes of illustration only and are not intended to limit the scope of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will become more fully understood from the detailed description and the accompanying drawings, wherein:

FIG. 1 depicts Fourier transform infrared spectra.

FIG. 2 depicts Fourier transform infrared spectra.

FIG. 3 depicts ³¹P NMR spectra of solutions with P:Sn molar ratios of 5 (A), 2 (B), and 1 (C).

FIG. 4 depicts ¹¹⁹Sn NMR spectra of solutions with P:Sn molar ratios of 5 (A), 2 (B), and 1 (C).

FIG. 5 is a Fourier transform infrared spectrum of SnF₂.

FIG. 6 depicts Raman spectra of water and solutions with P:Sn molar ratios of 1, 2, and 5 (from top to bottom: P:Sn molar ratio 5, P:Sn molar ratio 2, P:Sn molar ratio 1, and water).

FIG. 7 depicts a ³¹P NMR spectrum of a solution of TSPP.

DETAILED DESCRIPTION

The following description of the preferred embodiment(s) is merely exemplary in nature and is in no way intended to limit the invention, its application, or uses.

As used throughout, ranges are used as shorthand for describing each and every value that is within the range. Any value within the range can be selected as the terminus of the range. In addition, all references cited herein are hereby incorporated by reference in their entireties. In the event of a conflict in a definition in the present disclosure and that of a cited reference, the present disclosure controls.

Unless otherwise specified, all percentages and amounts expressed herein and elsewhere in the specification should be understood to refer to percentages by weight. The amounts given are based on the active weight of the material.

Provided is an aqueous soluble tin phosphate complex (Complex 1), e.g.,

-   -   1.1 Complex 1, wherein the complex is formed from a mixture         comprising tin (II) fluoride and a pyrophosphate salt, e.g., an         alkali pyrophosphate salt, e.g., tetrapotassium pyrophosphate or         tetrasodium pyrophosphate.     -   1.2 Complex 1 or 1.1, wherein the complex is formed from a         mixture comprising tin (II) fluoride and a pyrophosphate salt,         e.g., an alkali pyrophosphate salt, e.g., tetrapotassium         pyrophosphate or tetrasodium pyrophosphate, in an aqueous         solution.     -   1.3 Complex 1.2, wherein the aqueous solution has a pH from         5-11, e.g., 5-10, e.g., 5-9, e.g., 5-8, e.g., 5-7, e.g., 5-6,         e.g., 6-8, e.g., 6-7, e.g., 8-9, e.g., 9-10, e.g., 10-11.         Complex 1.2, wherein the pyrophosphate salt is tetrapotassium         pyrophosphate and the aqueous solution has a pH from 5-11, e.g.,         5-10, e.g., 5-9, e.g., 5-8, e.g., 5-7, e.g., 5-6, e.g., 6-8,         e.g., 6-7, e.g., 9-10, e.g., 10-11. Complex 1.2, wherein the         pyrophosphate salt is tetrasodium pyrophosphate and the aqueous         solution has a pH from 5-9, e.g., 5-8, e.g., 5-7, e.g., 5-6,         e.g., 6-8, e.g., 6-7, e.g., 8-9.     -   1.4 Any of the foregoing complexes, wherein the complex is         formed from a mixture comprising the tin (II) fluoride and         pyrophosphate salt in a molar ratio of at least 1P:1Sn, e.g.,         1P:1Sn to 15P:1Sn, e.g., 1P:1Sn to less than 15P:1Sn, e.g.,         1P:1Sn to 10P:1Sn, e.g., 1P:1Sn to less than 10P:1Sn, e.g.,         1P:1Sn to 5P:1Sn, e.g., 1P:1Sn to less than 5P: 1Sn, e.g.,         1P:1Sn to 2P:1Sn, e.g., 1P:1Sn, e.g., 2P:1Sn, e.g., 5P:1Sn,         e.g., 10P:1Sn, e.g., 15P:1Sn.     -   1.5 Any of the foregoing complexes, wherein the complex is         formed from a mixture comprising the tin (II) fluoride and         pyrophosphate salt in a molar ratio of 1P:1Sn to 15P:1Sn, e.g.,         1P:1Sn to 10P:1Sn, e.g., 1P:1Sn to less than 10P:1Sn, e.g.,         1P:1Sn to 5P:1Sn, e.g., 1P:1Sn to 2P:1Sn, e.g., 1P:1Sn, e.g.,         2P:1Sn, e.g., 5P:1Sn, e.g., 10P:1Sn, e.g., 15P:1Sn.     -   1.6 Any of the foregoing complexes, wherein the complex is         formed from a mixture comprising 1-10 weight % tin (II) fluoride         by weight of the mixture, e.g., 1-9 weight % tin (II) fluoride         by weight of the mixture, e.g., 2 weight % tin (II) fluoride by         weight of the mixture, and 1-40 weight % pyrophosphate salt by         weight of the mixture, e.g., 1-30 weight % pyrophosphate salt by         weight of the mixture, e.g., 1-20 weight % pyrophosphate salt by         weight of the mixture, e.g., 1-10 weight % pyrophosphate salt by         weight of the mixture.     -   1.7 Any of the foregoing complexes, wherein the complex is         formed from a mixture comprising tin (II) fluoride and         tetrapotassium pyrophosphate (K₄P₂O₇) (TKPP).     -   1.8 Complex 1.7, wherein the complex is formed from a mixture         comprising tin (II) fluoride and tetrapotassium pyrophosphate         (K₄P₂O₇) (TKPP) in a molar ratio of at least 1P:1Sn, e.g.,         1P:1Sn to 15P:1Sn, e.g., 1P:1Sn to less than 15P:1Sn, e.g.,         1P:1Sn to 10P:1Sn, e.g., 1P:1Sn to less than 10P:1Sn, e.g.,         1P:1Sn to 5P:1Sn, e.g., 1P:1Sn to less than 5P:1Sn, e.g., 1P:1Sn         to 2P:1Sn, e.g., 1P:1Sn, e.g., 2P:1Sn, e.g., 5P:1Sn, e.g.,         10P:1Sn, e.g., 15P:1Sn.     -   1.9 Complex 1.7 or 1.8, wherein the complex is formed from a         mixture comprising 1-10 weight % tin (II) fluoride by weight of         the mixture, e.g., 1-9 weight % tin (II) fluoride by weight of         the mixture, e.g., 2 weight % tin (II) fluoride by weight of the         mixture, and 1-40 weight % tetrapotassium pyrophosphate by         weight of the mixture, e.g., 1-30 weight % tetrapotassium         pyrophosphate by weight of the mixture, e.g., 1-20 weight %         tetrapotassium pyrophosphate by weight of the mixture, e.g.,         1-10 weight % tetrapotassium pyrophosphate by weight of the         mixture.     -   1.10 Any of Complex 1 or 1.1-1.6, wherein the complex is formed         from a mixture comprising tin (II) fluoride and tetrasodium         pyrophosphate.     -   1.11 Complex 1.10, wherein the complex is formed from a mixture         comprising tin (II) fluoride and tetrasodium pyrophosphate in a         molar ratio of 1P:1Sn to 10P:1Sn, e.g., 1P:1Sn to less than         10P:1Sn, e.g., 1P:1Sn to 5P:1Sn, e.g., 1P:1Sn to less than         5P:1Sn, e.g., 1P:1Sn to 2P:1Sn, e.g., 1P:1Sn, e.g., 2P:1Sn,         e.g., 5P:1Sn.     -   1.12 Complex 1.10 or 1.11, wherein the complex is formed from a         mixture comprising 1-10 weight % tin (II) fluoride by weight of         the mixture, e.g., 1-9 weight % tin (II) fluoride by weight of         the mixture, e.g., 2 weight % tin (II) fluoride by weight of the         mixture, and 1-30 weight % tetrasodium pyrophosphate by weight         of the mixture, e.g., 1-20 weight % tetrasodium pyrophosphate by         weight of the mixture, e.g., 1-10 weight % tetrasodium         pyrophosphate by weight of the mixture.     -   1.13 Any of the foregoing complexes, wherein the complex         exhibits a Fourier transform infrared spectrum substantially as         shown in the Sn-TSPP spectrum in FIG. 1.     -   1.14 Any of the foregoing complexes, wherein the complex         exhibits a Fourier transform infrared spectrum substantially as         shown in the Sn-TSPP spectrum in FIG. 2.     -   1.15 Any of the foregoing complexes, wherein the complex         exhibits a Fourier transform infrared spectrum comprising one or         more peaks selected from the group consisting of: 1181 cm⁻¹,         1013 cm⁻¹, 915 cm⁻¹, and 739 cm⁻¹.     -   1.16 Any of the foregoing complexes, wherein the complex         exhibits a Fourier transform infrared spectrum comprising one or         more peaks selected from the group consisting of: 3401 cm⁻¹,         1642 cm⁻¹, 1181 cm⁻¹, 1013 cm⁻¹, 915 cm⁻¹, and 739 cm⁻¹.     -   1.17 Any of the foregoing complexes, wherein the complex         exhibits a Fourier transform infrared spectrum comprising the         following peaks: 1181 cm⁻¹, 1013 cm⁻¹, 915 cm⁻¹, and 739 cm⁻¹.     -   1.18 Any of the foregoing complexes, wherein the complex         exhibits a Fourier transform infrared spectrum comprising the         following peaks: 3401 cm⁻¹, 1642 cm⁻¹, 1181 cm⁻, 1013 cm⁻¹, 915         cm⁻¹, and 739 cm⁻¹.     -   1.19 Any of the foregoing complexes, wherein the complex         exhibits a Fourier transform infrared spectrum comprising one or         more peaks selected from the group consisting of: 1101 cm⁻¹,         1081 cm⁻¹, 979 cm⁻¹, 722 cm⁻¹, 546 cm⁻¹, and 481 cm⁻¹.     -   1.20 Any of the foregoing complexes, wherein the complex         exhibits a Fourier transform infrared spectrum comprising the         following peaks: 1101 cm⁻¹, 1081 cm⁻¹, 979 cm⁻¹, 722 cm⁻¹, 546         cm⁻¹, and 481 cm⁻¹.     -   1.21 Any of the foregoing complexes, wherein the complex         exhibits a Fourier transform infrared spectrum comprising one or         more peaks selected from the group consisting of: 1101 cm⁻¹,         1081 cm⁻¹, 979 cm⁻¹, 881 cm⁻¹, 722 cm⁻¹, 546 cm⁻¹, and 481 cm⁻¹.     -   1.22 Any of the foregoing complexes, wherein the complex         exhibits a Fourier transform infrared spectrum comprising the         following peaks: 1101 cm⁻¹, 1081 cm⁻¹, 979 cm⁻¹, 881 cm⁻¹, 722         cm⁻¹, 546 cm⁻¹, and 481 cm⁻¹.     -   1.23 Any of the foregoing complexes, wherein the complex         exhibits a Raman spectrum substantially as shown in any of the         P/Sn Raman spectra of FIG. 6.     -   1.24 Any of the foregoing complexes, wherein the complex         exhibits a Raman spectrum comprising a peak at 1022 cm⁻¹.     -   1.25 Any of the foregoing complexes, wherein the complex         exhibits a ³¹P NMR spectrum as shown in any of the NMR spectra         of FIG. 3, A, 3, B, or 3, C, wherein the NMR spectrum is         obtained on an aqueous solution with 5 weight % D₂O added and is         externally referenced to 85% H₃PO₄ set to 0 ppm.     -   1.26 Any of the foregoing complexes, wherein the complex         exhibits a ³¹P NMR spectrum comprising the following peak: −6         ppm, e.g., −6.3 ppm, e.g., −6.30 ppm, wherein the NMR spectrum         is obtained on an aqueous solution with 5 weight % D₂O added and         is externally referenced to 85% H₃PO₄ set to 0 ppm.     -   1.27 Any of the foregoing complexes, wherein the complex         exhibits a ³¹P NMR spectrum comprising one or more peaks         selected from the group consisting of: −6 ppm, −10 ppm, and −10         ppm (doublet), e.g., −6.3 ppm, −9.8 ppm, −10.2 ppm (doublet),         and −10.3 ppm (doublet), e.g., −6.30 ppm, −9.82 ppm, −10.23 ppm         (doublet), and −10.31 ppm (doublet), wherein the NMR spectrum is         obtained on an aqueous solution with 5 weight % D₂O added and is         externally referenced to 85% H₃PO₄ set to 0 ppm.     -   1.28 Any of the foregoing complexes, wherein the complex         exhibits a ³¹P NMR spectrum comprising the following peaks: −6         ppm, −10 ppm, and −10 ppm (doublet), e.g., −6.3 ppm, −9.8 ppm,         −10.2 ppm (doublet), and -10.3 ppm (doublet), e.g., −6.30 ppm,         −9.82 ppm, −10.23 ppm (doublet), and -10.31 ppm (doublet),         wherein the NMR spectrum is obtained on an aqueous solution with         5 weight % D₂O added and is externally referenced to 85% H₃PO₄         set to 0 ppm.     -   1.29 Any of the foregoing complexes, wherein the complex         exhibits a ³¹P NMR spectrum comprising the following peak: −8         ppm, e.g., −8.3 ppm, e.g., −8.34 ppm, wherein the NMR spectrum         is obtained on an aqueous solution with 5 weight % D₂O added and         is externally referenced to 85% H₃PO₄ set to 0 ppm.     -   1.30 Any of the foregoing complexes, wherein the complex         exhibits a ³¹P NMR spectrum comprising one or more peaks         selected from the group consisting of: −8 ppm, −10 ppm, and −11         ppm, e.g., −8.3 ppm, −9.8 ppm, −10.5 ppm, −10.7 ppm, and -11.1         ppm, e.g., −8.34 ppm, −9.78 ppm, −10.49 ppm, −10.69 ppm, and         -11.09 ppm, wherein the NMR spectrum is obtained on an aqueous         solution with 5 weight % D₂O added and is externally referenced         to 85% H₃PO₄ set to 0 ppm.     -   1.31 Any of the foregoing complexes, wherein the complex         exhibits a ³¹P NMR spectrum comprising the following peaks: −8         ppm, −10 ppm, and −11 ppm, e.g., −8.3 ppm, −9.8 ppm, −10.5 ppm,         −10.7 ppm, and -11.1 ppm, e.g., −8.34 ppm, −9.78 ppm, −10.49         ppm, −10.69 ppm, and -11.09 ppm, wherein the NMR spectrum is         obtained on an aqueous solution with 5 weight % D₂O added and is         externally referenced to 85% H₃PO₄ set to 0 ppm.     -   1.32 Any of the foregoing complexes, wherein the complex         exhibits a ³¹P NMR spectrum comprising one or more peaks         selected from the group consisting of: 2 ppm, −9 ppm, −10 ppm,         −11 ppm, −13 ppm, and −14 ppm, e.g., 2.1 ppm, 2.2 ppm, −9.0 ppm,         −9.3 ppm, −9.7 ppm, −10.4 ppm, −11.2 ppm, −11.4 ppm, −12.8 ppm,         and -14.4 ppm, e.g., 2.10 ppm, 2.22 ppm, −9.03 ppm, −9.31 ppm,         −9.65 ppm, −9.74 ppm, −10.36 ppm, −11.22 ppm, −11.40 ppm, −12.77         ppm, and -14.35 ppm, wherein the NMR spectrum is obtained on an         aqueous solution with 5 weight % D₂O added and is externally         referenced to 85% H₃PO₄ set to 0 ppm.     -   1.33 Any of the foregoing complexes, wherein the complex         exhibits a ³¹P NMR spectrum comprising the following peaks: 2         ppm, −9 ppm, −10 ppm, −11 ppm, −13 ppm, and −14 ppm, e.g., 2.1         ppm, 2.2 ppm, −9.0 ppm, −9.3 ppm, −9.7 ppm, −10.4 ppm, −11.2         ppm, −11.4 ppm, −12.8 ppm, and -14.4 ppm, e.g., 2.10 ppm, 2.22         ppm, −9.03 ppm, −9.31 ppm, −9.65 ppm, −9.74 ppm, −10.36 ppm,         −11.22 ppm, −11.40 ppm, −12.77 ppm, and -14.35 ppm, wherein the         NMR spectrum is obtained on an aqueous solution with 5 weight %         D₂O added and is externally referenced to 85% H₃PO₄ set to 0         ppm.     -   1.34 Any of the foregoing complexes, wherein the complex         exhibits a ¹¹⁹Sn NMR spectrum as shown in any of the NMR spectra         of FIG. 4, A, 4, B, or 4, C, wherein the NMR spectrum is         obtained on an aqueous solution with 5 weight % D₂O added and is         externally referenced to saturated SnF₂ in D₂O at −796 ppm.     -   1.35 Any of the foregoing complexes, wherein the complex         exhibits a ¹¹⁹Sn NMR spectrum comprising the following peak:         −641 ppm, e.g., −640.6 ppm, e.g., −640.63 ppm, wherein the NMR         spectrum is obtained in an aqueous solution with 5 weight % D₂O         added and is externally referenced to saturated SnF₂ at −796         ppm.     -   1.36 Any of the foregoing complexes, wherein the complex         exhibits a ¹¹⁹Sn NMR spectrum comprising one or more peaks         selected from the group consisting of: −641 ppm, −687 ppm, and         −694 ppm, e.g., −640.6 ppm, −686.6 ppm, and -693.8 ppm, e.g.,         −640.63 ppm, −686.58 ppm, and -693.76 ppm, wherein the NMR         spectrum is obtained on an aqueous solution with 5 weight % D₂O         added and is externally referenced to saturated SnF₂ at −796         ppm.     -   1.37 Any of the foregoing complexes, wherein the complex         exhibits a ¹¹⁹Sn NMR spectrum comprising the following peaks:         −641 ppm, −687 ppm, and −694 ppm, e.g., −640.6 ppm, −686.6 ppm,         and -693.8 ppm, e.g., −640.63 ppm, −686.58 ppm, and -693.76 ppm,         wherein the NMR spectrum is obtained on an aqueous solution with         5 weight % D₂O added and is externally referenced to saturated         SnF₂ in D₂O at −796 ppm.     -   1.38 Any of the foregoing complexes, wherein the complex         exhibits a ¹¹⁹Sn NMR spectrum comprising the following peak:         −642 ppm, e.g., −642.4 ppm, e.g., −642.35 ppm, wherein the NMR         spectrum is obtained on an aqueous solution with 5 weight % D₂O         added and is externally referenced to saturated SnF₂ at −796         ppm.     -   1.39 Any of the foregoing complexes, wherein the complex         exhibits a ¹¹⁹Sn NMR spectrum comprising one or more peaks         selected from the group consisting of: −642 ppm, −679 ppm, and         −725 ppm, e.g., −642.4 ppm, −678.8 ppm, and -724.6 ppm, e.g.,         −642.35 ppm, −678.79 ppm, and -724.61 ppm, wherein the NMR         spectrum is obtained on an aqueous solution with 5 weight % D₂O         added and is externally referenced to saturated SnF₂ at −796         ppm.     -   1.40 Any of the foregoing complexes, wherein the complex         exhibits a ¹¹⁹Sn NMR spectrum comprising the following peaks:         −642 ppm, −679 ppm, and −725 ppm, e.g., −642.4 ppm, −678.8 ppm,         and -724.6 ppm, e.g., −642.35 ppm, −678.79 ppm, and -724.61 ppm,         wherein the NMR spectrum is obtained on an aqueous solution with         5 weight % D₂O added and is externally referenced to saturated         SnF₂ in D₂O at −796 ppm.     -   1.41 Any of the foregoing complexes, wherein the complex         exhibits a ¹¹⁹Sn NMR spectrum comprising one or more peaks         selected from the group consisting of: −673 ppm, −686 ppm, −696         ppm, −706 ppm, −735 ppm, −743 ppm, −748 ppm, −755 ppm, −764 ppm,         −767 ppm, −774 ppm, −805 ppm, −813 ppm, and −821 ppm, e.g.,         −673.0 ppm, −686.4 ppm, −696.1 ppm, −705.8 ppm, −734.9 ppm,         −742.9 ppm, −747.9 ppm, −755.0 ppm, −764.4 ppm, −766.7 ppm,         −773.8 ppm, −804.8 ppm, −813.1 ppm, and -821.5 ppm, e.g.,         −672.97 ppm, −686.36 ppm, −696.08 ppm, −705.84 ppm, −734.85 ppm,         −742.85 ppm, −747.93 ppm, −754.99 ppm, −764.39 ppm, −766.74 ppm,         −773.79 ppm, −804.84 ppm, −813.14 ppm, and -821.45 ppm, wherein         the NMR spectrum is obtained on an aqueous solution with 5         weight % D₂O added and is externally referenced to saturated         SnF₂ at −796 ppm.     -   1.42 Any of the foregoing complexes, wherein the complex         exhibits a ¹¹⁹Sn NMR spectrum comprising the following peaks:         −673 ppm, −686 ppm, −696 ppm, −706 ppm, −735 ppm, −743 ppm, −748         ppm, −755 ppm, −764 ppm, −767 ppm, −774 ppm, −805 ppm, −813 ppm,         and −821 ppm, e.g., −673.0 ppm, −686.4 ppm, −696.1 ppm, −705.8         ppm, −734.9 ppm, −742.9 ppm, −747.9 ppm, −755.0 ppm, −764.4 ppm,         −766.7 ppm, −773.8 ppm, −804.8 ppm, −813.1 ppm, and -821.5 ppm,         e.g., −672.97 ppm, −686.36 ppm, −696.08 ppm, −705.84 ppm,         −734.85 ppm, −742.85 ppm, −747.93 ppm, −754.99 ppm, −764.39 ppm,         −766.74 ppm, −773.79 ppm, −804.84 ppm, −813.14 ppm, and -821.45         ppm, wherein the NMR spectrum is obtained on an aqueous solution         with 5 weight % D₂O added and is externally referenced to         saturated SnF₂ in D₂O at −796 ppm.     -   1.43 Any of the foregoing complexes, wherein the complex is         [P₂O₇]⁴⁻Na⁺Sn²⁺ ₂F⁻.     -   1.44 Any of the foregoing complexes, wherein the complex is         isolated.     -   1.45 Any of the foregoing complexes, wherein the complex is         lyophilized.     -   1.46 Any of the foregoing complexes, wherein the complex is         isolated with an anti-solvent, e.g., an organic solvent, e.g.,         ethanol.     -   1.47 Any of the foregoing complexes for use in an oral care         composition, e.g., mouthwash, oral gel, or dentifrice.     -   1.48 Any of the foregoing complexes for use to reduce or inhibit         dentinal hypersensitivity, dental caries, gingivitis, or plaque.

Further provided is a method (Method 1a) to reduce or inhibit or more of dentinal hypersensitivity, dental caries, gingivitis, and plaque in a person in need thereof comprising administering an effective amount of any of Complex 1 et seq. to the oral cavity of the person.

Further provided is a method (Method 1b) of occluding dentin tubules in a person in need thereof comprising administering an effective amount of any of Complex 1 et seq. to the oral cavity of the person.

Further provided is a method (Method 2) of making an aqueous soluble tin phosphate complex, e.g., any of Complex 1 et seq., comprising combining tin (II) fluoride and a pyrophosphate salt, e.g., an alkali pyrophosphate salt, e.g., tetrapotassium pyrophosphate (K₄P₂O₇) (TKPP) or tetrasodium pyrophosphate (Na₄P₂O₇) (TSPP), e.g.,

-   -   2.1 Method 2 comprising combining the tin (II) fluoride and         pyrophosphate salt, e.g., alkali pyrophosphate salt, in an         aqueous solution.     -   2.2 Method 2.1, wherein the aqueous solution has a pH from 5-11,         e.g., 5-10, e.g., 5-9, e.g., 5-8, e.g., 5-7, e.g., 5-6, e.g.,         6-8, e.g., 6-7, e.g., 8-9, e.g., 9-10, e.g., 10-11. Method 2.1,         wherein the pyrophosphate salt is tetrapotassium pyrophosphate         and the aqueous solution has a pH from 5-11, e.g., 5-10, e.g.,         5-9, e.g., 5-8, e.g., 5-7, e.g., 5-6, e.g., 6-8, e.g., 6-7,         e.g., 9-10, e.g., 10-11. Method 2.1, wherein the pyrophosphate         salt is tetrasodium pyrophosphate and the aqueous solution has a         pH from 5-9, e.g., 5-8, e.g., 5-7, e.g., 5-6, e.g., 6-8, e.g.,         6-7, e.g., 8-9.     -   2.3 Any of the foregoing methods comprising combining the         tin (II) fluoride and pyrophosphate salt in a molar ratio of at         least 1P:1Sn, e.g., 1P:1Sn to 15P:1Sn, e.g., 1P:1Sn to less than         15P:1Sn, e.g., 1P:1Sn to 10P:1Sn, e.g., 1P:1Sn to less than         10P:1Sn, e.g., 1P:1Sn to 5P:1Sn, e.g., 1P:1Sn to less than         5P:1Sn, e.g., 1P:1Sn to 2P:1Sn, e.g., 1P:1Sn, e.g., 2P:1Sn,         e.g., 5P:1Sn, e.g., 10P:1Sn, e.g., 15P:1Sn.     -   2.4 Any of the foregoing methods comprising combining the         tin (II) fluoride and pyrophosphate salt in a molar ratio of         1P:1Sn to 15P:1Sn, e.g., 1P:1Sn to 10P:1Sn, e.g., 1P:1Sn to less         than 10P:1Sn, e.g., 1P:1Sn to 5P:1Sn, e.g., 1P:1Sn to 2P:1Sn,         e.g., 1P:1Sn, e.g., 2P:1Sn, e.g., 5P:1Sn, e.g., 10P:1Sn, e.g.,         15P:1Sn.     -   2.5 Any of the foregoing methods comprising combining 1-10         weight % tin (II) fluoride by weight of the combination, e.g.,         1-9 weight % tin (II) fluoride by weight of the combination,         e.g., 2 weight % tin (II) fluoride by weight of the combination,         and 1-40 weight % pyrophosphate salt by weight of the         combination, e.g., 1-30 weight % pyrophosphate salt by weight of         the combination, e.g., 1-20 weight % pyrophosphate salt by         weight of the combination, e.g., 1-10 weight % pyrophosphate         salt by weight of the combination.     -   2.6 Any of the foregoing methods, wherein the pyrophosphate salt         is tetrapotassium pyrophosphate (K₄P₂O₇).     -   2.7 Method 2.6 comprising combining the tin (II) fluoride and         tetrapotassium pyrophosphate in a molar ratio of at least         1P:1Sn, e.g., 1P:1Sn to 15P:1Sn, e.g., 1P:1Sn to less than         15P:1Sn, e.g., 1P:1Sn to 10P:1Sn, e.g., 1P:1Sn to less than         10P:1Sn, e.g., 1P:1Sn to 5P:1Sn, e.g., 1P:1Sn to less than         5P:1Sn, e.g., 1P:1Sn to 2P:1Sn, e.g., 1P:1Sn, e.g., 2P:1Sn,         e.g., 5P:1Sn, e.g., 10P:1Sn, e.g., 15P:1Sn.     -   2.8 Method 2.6 or 2.7 comprising combining 1-10 weight %         tin (II) fluoride by weight of the combination, e.g., 1-9 weight         % tin (II) fluoride by weight of the combination, e.g., 2 weight         % tin (II) fluoride by weight of the combination, and 1-40         weight % tetrapotassium pyrophosphate by weight of the         combination, e.g., 1-30 weight % tetrapotassium pyrophosphate by         weight of the combination, e.g., 1-20 weight % tetrapotassium         pyrophosphate by weight of the combination, e.g., 1-10 weight %         tetrapotassium pyrophosphate by weight of the combination.     -   2.9 Any of Method 2 or 2.1-2.5, wherein the pyrophosphate salt         is tetrasodium pyrophosphate (Na₄P₂O₇).     -   2.10 Method 2.9 comprising combining the tin (II) fluoride and         tetrasodium pyrophosphate in a molar ratio of 1P:1Sn to 10P:1Sn,         e.g., 1P:1Sn to less than 10P:1Sn, e.g., 1P:1Sn to 5P:1Sn, e.g.,         1P:1Sn to less than 5P:1Sn, e.g., 1P:1Sn to 2P:1Sn, e.g.,         1P:1Sn, e.g., 2P:1Sn, e.g., 5P:1Sn.     -   2.11 Method 2.9 or 2.10 comprising combining 1-10 weight %         tin (II) fluoride by weight of the combination, e.g., 1-9 weight         % tin (II) fluoride by weight of the combination, e.g., 2 weight         % tin (II) fluoride by weight of the combination, and 1-30         weight % tetrasodium pyrophosphate by weight of the combination,         e.g., 1-20 weight % tetrasodium pyrophosphate by weight of the         combination, e.g., 1-10 weight % tetrasodium pyrophosphate by         weight of the combination.     -   2.12 Any of the foregoing methods comprising isolating the         complex in solid form.     -   2.13 Any of the foregoing methods comprising lyophilizing the         complex.     -   2.14 Any of the foregoing methods comprising isolating the         complex with an anti-solvent, e.g., an organic solvent, e.g.,         ethanol.     -   2.15 An oral care composition, e.g., a mouthwash, oral gel, or         dentifrice, e.g., a mouthwash, comprising an aqueous soluble tin         phosphate complex made as described in any of the foregoing         methods.

Further provided is an aqueous soluble tin phosphate complex made by any of Method 2 et seq.

Further provided is an oral care composition (Composition 1) comprising an aqueous soluble tin phosphate complex formed from a mixture comprising tin (II) fluoride and a pyrophosphate salt, e.g., an alkali pyrophosphate salt, e.g., tetrapotassium pyrophosphate (K₄P₂O₇) or tetrasodium pyrophosphate (Na₄P₂O₇), e.g., any of Complex 1 et seq., e.g.,

-   -   1.1 Composition 1, wherein the complex is formed in the         composition in situ.     -   1.2 Composition 1, wherein the complex is formed in situ in an         aqueous solution and combined with the composition.     -   1.3 Composition 1 or 1.2, wherein the complex is combined as a         solid with the composition, e.g., wherein the complex is         isolated from the aqueous solution in solid form and combined         with the composition.     -   1.4 Any of Composition 1, 1.2, or 1.3, wherein the complex is         lyophilized and combined with the composition.     -   1.5 Any of Composition 1 or 1.2-1.4, wherein the complex is         isolated with an anti-solvent, e.g., an organic solvent, e.g.,         ethanol, and combined with the composition.     -   1.6 Any of the foregoing compositions, wherein the complex is         made as described in any of Method 2 et seq.     -   1.7 Any of the foregoing compositions, wherein the complex is         present in an amount of 2-30 weight % by weight of the         composition.     -   1.8 Any of the foregoing compositions, wherein the complex is         formed from the tin (II) fluoride and pyrophosphate salt in a         molar ratio of at least 1P:1Sn, e.g., 1P:1Sn to 15P:1Sn, e.g.,         1P:1Sn to less than 15P:1Sn, e.g., 1P:1Sn to 10P:1Sn, e.g.,         1P:1Sn to less than 10P:1Sn, e.g., 1P:1Sn to 5P:1Sn, e.g.,         1P:1Sn to less than 5P:1Sn, e.g., 1P:1Sn to 2P:1Sn, e.g.,         1P:1Sn, e.g., 2P:1Sn, e.g., 5P:1Sn, e.g., 10P:1Sn, e.g.,         15P:1Sn.     -   1.9 Any of the foregoing compositions, wherein the complex is         formed from the tin (II) fluoride and pyrophosphate salt in a         molar ratio of 1P:1Sn to 15P:1Sn, e.g., 1P:1Sn to 10P:1Sn, e.g.,         1P:1Sn to less than 10P:1Sn, e.g., 1P:1Sn to 5P:1Sn, e.g.,         1P:1Sn to 2P:1Sn, e.g., 1P:1Sn, e.g., 2P:1Sn, e.g., 5P:1Sn,         e.g., 10P:1Sn, e.g., 15P:1Sn.     -   1.10 Any of the foregoing compositions, wherein the complex is         formed from a mixture comprising 1-10 weight % tin (II) fluoride         by weight of the mixture, e.g., 1-9 weight % tin (II) fluoride         by weight of the mixture, e.g., 2 weight % tin (II) fluoride by         weight of the mixture, and 1-40 weight % pyrophosphate salt by         weight of the mixture, e.g., 1-30 weight % pyrophosphate salt by         weight of the mixture, e.g., 1-20 weight % pyrophosphate salt by         weight of the mixture, e.g., 1-10 weight % pyrophosphate salt by         weight of the mixture.     -   1.11 Any of the foregoing compositions, wherein the         pyrophosphate salt is tetrapotassium pyrophosphate (K₄P₂O₇).     -   1.12 Composition 1.11, wherein the complex is formed from the         tin (II) fluoride and tetrapotassium pyrophosphate in a molar         ratio of at least 1P:1Sn, e.g., 1P:1Sn to 15P:1Sn, e.g., 1P:1Sn         to less than 15P:1Sn, e.g., 1P:1Sn to 10P:1Sn, e.g., 1P:1Sn to         less than 10P:1Sn, e.g., 1P:1Sn to 5P:1Sn, e.g., 1P:1Sn to less         than 5P:1Sn, e.g., 1P:1Sn to 2P:1Sn, 1P:1Sn, e.g., 2P:1Sn, e.g.,         5P:1Sn, e.g., 10P:1Sn, e.g., 15P:1Sn.     -   1.13 Composition 1.11 or 1.12, wherein the complex is formed         from a mixture comprising 1-10 weight % tin (II) fluoride by         weight of the mixture, e.g., 1-9 weight % tin (II) fluoride by         weight of the mixture, e.g., 2 weight % tin (II) fluoride by         weight of the mixture, and 1-40 weight % tetrapotassium         pyrophosphate by weight of the mixture, e.g., 1-30 weight %         tetrapotassium pyrophosphate by weight of the mixture, e.g.,         1-20 weight % tetrapotassium pyrophosphate by weight of the         mixture, e.g., 1-10 weight % tetrapotassium pyrophosphate by         weight of the mixture.     -   1.14 Any of Composition 1 or 1.1-1.10, wherein the pyrophosphate         salt is tetrasodium pyrophosphate (Na₄P₂O₇).     -   1.15 Composition 1.14, wherein the complex is formed from a         mixture comprising the tin (II) fluoride and tetrasodium         pyrophosphate in a molar ratio of 1P:1Sn to 10P:1Sn, e.g.,         1P:1Sn to less than 10P:1Sn, e.g., 1P:1Sn to 5P:1Sn, e.g.,         1P:1Sn to less than 5P:1Sn, e.g., 1P:1Sn to 2P:1Sn, e.g.,         1P:1Sn, e.g., 2P:1Sn, e.g., 5P:1Sn.     -   1.16 Composition 1.14 or 1.15, wherein the complex is formed         from a mixture comprising 1-10 weight % tin (II) fluoride by         weight of the mixture, e.g., 1-9 weight % tin (II) fluoride by         weight of the mixture, e.g., 2 weight % tin (II) fluoride by         weight of the mixture, and 1-30 weight % tetrasodium         pyrophosphate by weight of the mixture, e.g., 1-20 weight %         tetrasodium pyrophosphate by weight of the mixture, e.g., 1-10         weight % tetrasodium pyrophosphate by weight of the mixture.     -   1.17 Any of the foregoing compositions, wherein the composition         comprises an aqueous solution.     -   1.18 Any of the foregoing compositions further comprising         another fluoride ion source, e.g., a fluoride ion source         selected from stannous fluoride, sodium fluoride, potassium         fluoride, sodium monofluorophosphate, sodium fluorosilicate,         ammonium fluorosilicate, amine fluoride (e.g.,         N′-octadecyltrimethylendiamine-N,N,N′-tris(2-ethanol)-dihydrofluoride),         ammonium fluoride, titanium fluoride, hexafluorosulfate, and         combinations thereof.     -   1.19 Composition 1.18, wherein the fluoride ion source is         present in an amount of 0.01-5 weight % by weight of the         composition, e.g., 0.01-2 weight % by weight of the composition,         e.g., 0.01-1 weight % by weight of the composition.     -   1.20 Any of the foregoing compositions further comprising         another alkali phosphate salt.     -   1.21 Composition 1.20, wherein the alkali phosphate salt is         present in an amount of 1-10 weight % by weight of the         composition.     -   1.22 Any of the foregoing compositions further comprising a         humectant, e.g., a humectant selected from glycerin, sorbitol,         propylene glycol, polyethylene glycol, xylitol, and combinations         thereof     -   1.23 Composition 1.22, wherein the humectant is present in an         amount of 2-50 weight % by weight of the composition, e.g.,         10-40 weight % by weight of the composition, e.g., 15-30 weight         % by weight of the composition.     -   1.24 Any of the foregoing compositions further comprising a         surfactant, e.g., selected from anionic, cationic, zwitterionic,         and nonionic surfactants, and combinations thereof, e.g.,         selected from sodium lauryl sulfate, sodium ether lauryl         sulfate, cocamidopropylbetaine, a poloxamer, and combinations         thereof     -   1.25 Composition 1.24, wherein the surfactant is present in an         amount of 1-10 weight % by weight of the composition.     -   1.26 Any of the foregoing compositions further comprising a         thickener, e.g., selected from a polysaccharide gums, e.g.,         xanthan gum and/or carrageenan, a silica thickener, a cellulosic         polymer, e.g., sodium CMC, and combinations thereof.     -   1.27 Composition 1.26, wherein the thickener is present in an         amount of 1-10 weight % by weight of the composition.     -   1.28 Any of the foregoing compositions further comprising an         abrasive, e.g., silica abrasive.     -   1.29 Composition 1.28, wherein the abrasive is present in an         amount of 10-30 weight % by weight of the composition.     -   1.30 Any of the foregoing compositions further comprising a pH         agent to adjust the pH, e.g., selected from sodium bicarbonate,         an alkali phosphate, sodium hydroxide, citric acid, sodium         citrate, and combinations thereof.     -   1.31 Composition 1.30, wherein the pH agent is present in an         amount of 0.1-10 weight % by weight of the composition, e.g.,         1-5 weight % by weight of the composition, e.g., 1-3 weight % by         weight of the composition.     -   1.32 Any of the foregoing compositions further comprising         flavoring, fragrance, and/or coloring.     -   1.33 Any of the foregoing compositions further comprising 2-90         weight % water by weight of the composition, e.g., 2-50 weight %         water by weight of the composition, e.g., 50-80 weight % water         by weight of the composition.     -   1.34 Any of the foregoing compositions comprising more than 20         weight % water by weight of the composition, e.g., at least 30         weight % water by weight of the composition, e.g., at least 40         weight % water by weight of the composition, e.g., at least 50         weight % water by weight of the composition, e.g., at least 60         weight % water by weight of the composition, e.g., at least 70         weight % water by weight of the composition.     -   1.35 Any of the foregoing compositions, wherein the composition         has a pH from 5-11, e.g., 5-10, e.g., 5-9, e.g., 5-8, e.g., 5-7,         e.g., 5-6, e.g., 6-8, e.g., 6-7, e.g., 8-9, e.g., 9-10, e.g.,         10-11.     -   1.36 Any of the foregoing compositions, wherein the         pyrophosphate salt is tetrapotassium pyrophosphate and the         composition has a pH from 5-11, e.g., 5-10, e.g., 5-9, e.g.,         5-8, e.g., 5-7, e.g., 5-6, e.g., 6-8, e.g., 6-7, e.g., 9-10,         e.g., 10-11.     -   1.37 Any of Composition 1 or 1.1-1.35, wherein the pyrophosphate         salt is tetrasodium pyrophosphate and the composition has a pH         from 5-9, e.g., 5-8, e.g., 5-7, e.g., 5-6, e.g., 6-8, e.g., 6-7,         e.g., 8-9.     -   1.38 Any of the foregoing compositions, wherein the composition         is a mouthwash, oral gel, or dentifrice, e.g., a mouthwash.     -   1.39 Any of the foregoing compositions for use to reduce or         inhibit dentinal hypersensitivity, dental caries, gingivitis, or         plaque.

Further provided is a method (Method 3a) to reduce or inhibit one or more of dentinal hypersensitivity, dental caries, gingivitis, and plaque in a person in need thereof comprising administering an effective amount of an oral care composition comprising an aqueous soluble tin phosphate complex formed from a mixture comprising tin (II) fluoride and a pyrophosphate salt, e.g., an alkali pyrophosphate salt, e.g., tetrapotassium pyrophosphate (K₄P₂O₇) (TKPP) or tetrasodium pyrophosphate (Na₄P₂O₇) (TSPP), e.g., any of Composition 1 et seq., to the oral cavity of the person.

Further provided is a method (Method 3b) of occluding dentin tubules in a person in need thereof comprising administering an effective amount of an oral care composition comprising an aqueous soluble tin phosphate complex formed from a mixture comprising tin (II) fluoride and a pyrophosphate salt, e.g., an alkali pyrophosphate salt, e.g., tetrapotassium pyrophosphate (K₄P₂O₇) (TKPP) or tetrasodium pyrophosphate (Na₄P₂O₇) (TSPP), e.g., any of Composition 1 et seq., to the oral cavity of the person.

Further provided is Method 3a and/or 3b as follows:

-   -   3.1 Any of Method 3a or 3b, wherein the complex is any of         Complex 1 et seq.     -   3.2 Any of Method 3a, 3b, or 3.1, wherein the complex is formed         in situ in the composition, e.g., wherein the composition has a         pH from 5-11, e.g., 5-10, e.g., 5-9, e.g., 5-8, e.g., 5-7, e.g.,         5-6, e.g., 6-8, e.g., 6-7, e.g., 8-9, e.g., 9-10, e.g., 10-11.         Any of Method 3a, 3b, or 3.1, wherein the pyrophosphate salt is         tetrapotassium pyrophosphate and the composition has a pH from         5-11, e.g., 5-10, e.g., 5-9, e.g., 5-8, e.g., 5-7, e.g., 5-6,         e.g., 6-8, e.g., 6-7, e.g., 9-10, e.g., 10-11. Any of Method 3a,         3b, or 3.1, wherein the pyrophosphate salt is tetrasodium         pyrophosphate and the composition has a pH from 5-9, e.g., 5-8,         e.g., 5-7, e.g., 5-6, e.g., 6-8, e.g., 6-7, e.g., 8-9.     -   3.3 Any of Method 3a, 3b, or 3.1, wherein the complex is formed         in situ in an aqueous solution and combined with the         composition, e.g., wherein the aqueous solution has a pH from         5-11, e.g., 5-10, e.g., 5-9, e.g., 5-8, e.g., 5-7, e.g., 5-6,         e.g., 6-8, e.g., 6-7, e.g., 8-9, e.g., 9-10, e.g., 10-11. Any of         Method 3a, 3b, or 3.1, wherein the pyrophosphate salt is         tetrapotassium pyrophosphate and the aqueous solution has a pH         from 5-11, e.g., 5-10, e.g., 5-9, e.g., 5-8, e.g., 5-7, e.g.,         5-6, e.g., 6-8, e.g., 6-7, e.g., 9-10, e.g., 10-11. Any of         Method 3a, 3b, or 3.1, wherein the pyrophosphate salt is         tetrasodium pyrophosphate and the aqueous solution has a pH from         5-9, e.g., 5-8, e.g., 5-7, e.g., 5-6, e.g., 6-8, e.g., 6-7,         e.g., 8-9.     -   3.4 Any of Method 3a, 3b, 3.1, or 3.3, wherein the complex is         combined as a solid with the composition, e.g., wherein the         complex is isolated from the aqueous solution in solid form and         combined with the composition, e.g., mouthwash.     -   3.5 Any of Method 3a, 3b, 3.1, 3.3, or 3.4, wherein the complex         is lyophilized and combined with the composition.     -   3.6 Any of Method 3a, 3b, 3.1, or 3.3-3.5, wherein the complex         is isolated with an anti-solvent, e.g., an organic solvent,         e.g., ethanol, and combined with the composition.     -   3.7 Any of the foregoing methods, wherein the complex is made as         described in any of Method 2 et seq.     -   3.8 Any of the foregoing methods, wherein the complex is present         in an amount of 2-30 weight % by weight of the composition.     -   3.9 Any of the foregoing methods, wherein the complex is formed         from a mixture comprising the tin (II) fluoride and         pyrophosphate salt in a molar ratio of at least 1P:1Sn, e.g.,         1P:1Sn to 15P:1Sn, e.g., 1P:1Sn to less than 15P:1Sn, e.g.,         1P:1Sn to 10P:1Sn, e.g., 1P:1Sn to less than 10P:1Sn, e.g.,         1P:1Sn to 5P:1Sn, e.g., 1P:1Sn to less than 5P:1Sn, e.g., 1P:1Sn         to 2P:1Sn, e.g., 1P:1Sn, e.g., 2P:1Sn, e.g., 5P:1Sn, e.g.,         10P:1Sn, e.g., 15P:1Sn.     -   3.10 Any of the foregoing methods, wherein the complex is formed         from a mixture comprising the tin (II) fluoride and         pyrophosphate salt in a molar ratio of 1P:1Sn to 15P:1Sn, e.g.,         1P:1Sn to 10P:1Sn, e.g., 1P:1Sn to less than 10P:1Sn, e.g.,         1P:1Sn to 5P:1Sn, e.g., 1P:1Sn to 2P:1Sn, e.g., 1P:1Sn, e.g.,         2P:1Sn, e.g., 5P:1Sn, e.g., 10P:1Sn, e.g., 15P:1Sn.     -   3.11 Any of the foregoing methods, wherein the complex is formed         from a mixture comprising 1-10 weight % tin (II) fluoride by         weight of the mixture, e.g., 1-9 weight % tin (II) fluoride by         weight of the mixture, e.g., 2 weight % tin (II) fluoride by         weight of the mixture, and 1-10 weight % pyrophosphate salt by         weight of the mixture, e.g., 3-4 weight % pyrophosphate salt by         weight of the mixture, e.g., 7-8 weight % pyrophosphate salt by         weight of the mixture.     -   3.12 Any of the foregoing methods, wherein the pyrophosphate         salt is tetrapotassium pyrophosphate.     -   3.13 Method 3.12, wherein the complex is formed from a mixture         comprising the tin (II) fluoride and tetrapotassium         pyrophosphate in a molar ratio of at least 1P:1Sn, e.g., 1P:1Sn         to 15P:1Sn, e.g., 1P:1Sn to less than 15P:1Sn, e.g., 1P:1Sn to         10P:1Sn, e.g., 1P:1Sn to less than 10P:1Sn, e.g., 1P:1Sn to         5P:1Sn, e.g., 1P:1Sn to less than 5P:1Sn, e.g., 1P:1Sn to         2P:1Sn, e.g., 1P:1Sn, e.g., 2P:1Sn, e.g., 5P:1Sn, e.g., 10P:1Sn,         e.g., 15P:1Sn.     -   3.14 Method 3.12 or 3.13, wherein the complex is formed from a         mixture comprising 1-10 weight % tin (II) fluoride by weight of         the mixture, e.g., 1-9 weight % tin (II) fluoride by weight of         the mixture, e.g., 2 weight % tin (II) fluoride by weight of the         mixture, and 1-40 weight % tetrapotassium pyrophosphate by         weight of the mixture, e.g., 1-30 weight % tetrapotassium         pyrophosphate by weight of the mixture, e.g., 1-20 weight %         tetrapotassium pyrophosphate by weight of the mixture, e.g.,         1-10 weight % tetrapotassium pyrophosphate by weight of the         mixture.     -   3.15 Any of Method 3a, 3b, or 3.1-3.11, wherein the         pyrophosphate salt is tetrasodium pyrophosphate.     -   3.16 Method 3.15, wherein the complex is formed from a mixture         comprising the tin (II) fluoride and tetrasodium pyrophosphate         in a molar ratio of 1P:1Sn to 10P:1Sn, e.g., 1P:1Sn to less than         10P:1Sn, e.g., 1P:1Sn to 5P:1Sn, e.g., 1P:1Sn to less than         5P:1Sn, e.g., 1P:1Sn to 2P:1Sn, e.g., 1P:1Sn, e.g., 2P:1Sn,         e.g., 5P:1Sn.     -   3.17 Method 3.15 or 3.16, wherein the complex is formed from a         mixture comprising 1-10 weight % tin (II) fluoride by weight of         the composition, e.g., 1-9 weight % tin (II) fluoride by weight         of the composition, e.g., 2 weight % tin (II) fluoride by weight         of the composition, and 1-30 weight % tetrasodium pyrophosphate         by weight of the composition, e.g., 1-20 weight % tetrasodium         pyrophosphate by weight of the composition, e.g., 1-10 weight %         tetrasodium pyrophosphate by weight of the composition.     -   3.18 Any of the foregoing methods, wherein the composition         further comprises another fluoride ion source, e.g., a fluoride         ion source selected from stannous fluoride, sodium fluoride,         potassium fluoride, sodium monofluorophosphate, sodium         fluorosilicate, ammonium fluorosilicate, amine fluoride (e.g.,         N′-octadecyltrimethylendiamine-N,N,N′-tris(2-ethanol)-dihydrofluoride),         ammonium fluoride, titanium fluoride, hexafluorosulfate, and         combinations thereof     -   3.19 Method 3.18, wherein the fluoride ion source is present in         an amount of 0.01-5 weight % by weight of the composition, e.g.,         0.01-2 weight % by weight of the composition, e.g., 0.01-1         weight % by weight of the composition.     -   3.20 Any of the foregoing methods, wherein the composition         further comprises another alkali phosphate salt.     -   3.21 Method 3.20, wherein the alkali phosphate salt is present         in an amount of 1-10 weight % by weight of the composition.     -   3.22 Any of the foregoing methods, wherein the composition         further comprises a humectant, e.g., a humectant selected from         glycerin, sorbitol, propylene glycol, polyethylene glycol,         xylitol, and combinations thereof.     -   3.23 Method 3.22, wherein the humectant is present in an amount         of 2-50 weight % by weight of the composition, e.g., 10-40         weight % by weight of the composition, e.g., 15-30 weight % by         weight of the composition.     -   3.24 Any of the foregoing methods, wherein the composition         further comprises a surfactant, e.g., selected from anionic,         cationic, zwitterionic, and nonionic surfactants, and         combinations thereof, e.g., selected from sodium lauryl sulfate,         sodium ether lauryl sulfate, cocamidopropylbetaine, a poloxamer,         and combinations thereof.     -   3.25 Method 3.24 wherein the surfactant is present in an amount         of 1-10 weight % by weight of the composition.     -   3.26 Any of the foregoing methods, wherein the composition         further comprises a thickener, e.g., selected from a         polysaccharide gums, e.g., xanthan gum and/or carrageenan, a         silica thickener, a cellulosic polymer, e.g., sodium CMC, and         combinations thereof     -   3.27 Method 3.26, wherein the thickener is present in an amount         of 1-10 weight % by weight of the composition.     -   3.28 Any of the foregoing methods, wherein the composition         further comprises an abrasive, e.g., silica abrasive.     -   3.29 Method 3.28, wherein the abrasive is present in an amount         of 10-30 weight % by weight of the composition.     -   3.30 Any of the foregoing methods, wherein the composition         further comprises a pH agent to adjust the pH, e.g., selected         from sodium bicarbonate, an alkali phosphate, sodium hydroxide,         citric acid, sodium citrate, and combinations thereof     -   3.31 Method 3.30, wherein the pH agent is present in an amount         of 0.1-10 weight % by weight of the composition, e.g., 1-5         weight % by weight of the composition, e.g., 1-3 weight % by         weight of the composition.     -   3.32 Any of the foregoing methods, wherein the composition         further comprises flavoring, fragrance, and/or coloring.     -   3.33 Any of the foregoing methods, wherein the composition         further comprises 2-90 weight % water by weight of the         composition, e.g., 2-50 weight % water by weight of the         composition, e.g., 50-80 weight % water by weight of the         composition.     -   3.34 Any of the foregoing methods, wherein the composition         further comprises more than 20 weight % water by weight of the         composition, e.g., at least 30 weight % water by weight of the         composition, e.g., at least 40 weight % water by weight of the         composition, e.g., at least 50 weight % water by weight of the         composition, e.g., at least 60 weight % water by weight of the         composition, e.g., at least 70 weight % water by weight of the         composition.     -   3.35 Any of the foregoing methods, wherein the composition         comprises an aqueous solution.     -   3.36 Any of the foregoing methods, wherein the pH of the         composition is from 5-11, e.g., 5-10, e.g., 5-9, e.g., 5-6,         e.g., 6-7, e.g., 8-9, e.g., 9-10, e.g., 10-11.     -   3.37 Any of the foregoing methods, wherein the pyrophosphate         salt is tetrapotassium pyrophosphate and the composition has a         pH from 5-11, e.g., 5-10, e.g., 5-9, e.g., 5-6, e.g., 6-7, e.g.,         9-10, e.g., 10-11.     -   3.38 Any of Method 3 or 3.1-3.36, wherein the pyrophosphate salt         is tetrasodium pyrophosphate and the composition has a pH from         5-9, e.g., 5-6, e.g., 6-7, e.g., 8-9.     -   3.39 Any of the foregoing methods, wherein the composition is         any of Composition 1 et seq.     -   3.40 Any of the foregoing methods, wherein the composition is a         mouthwash, oral gel, or dentifrice, e.g., a mouthwash.     -   3.41 Any of the foregoing methods to reduce or inhibit dentinal         hypersensitivity.     -   3.42 Any of the foregoing methods to reduce or inhibit dental         caries.     -   3.43 Any of the foregoing methods to reduce or inhibit         gingivitis.     -   3.44 Any of the foregoing methods to reduce or inhibit plaque.     -   3.45 Any of the foregoing methods to occlude dentin tubules.

Further provided is a method (Method 4) of making an oral care composition, e.g., any of Composition 1 et seq., comprising an aqueous soluble tin phosphate complex, e.g., any of Complex 1 et seq., comprising combining the complex, e.g., any of Complex 1 et seq., with an oral care base, e.g., a mouthwash, oral gel, or dentifrice base, e.g.,

-   -   4.1 Method 4, wherein the complex is formed in situ in the         composition, e.g., wherein the composition has a pH from 5-11,         e.g., 5-10, e.g., 5-9, e.g., 5-8, e.g., 5-7, e.g., 5-6, e.g.,         6-8, e.g., 6-7, e.g., 8-9, e.g., 9-10, e.g., 10-11. Method 4,         wherein the pyrophosphate salt is tetrapotassium pyrophosphate         and the composition has a pH from 5-11, e.g., 5-10, e.g., 5-9,         e.g., 5-8, e.g., 5-7, e.g., 5-6, e.g., 6-8, e.g., 6-7, e.g.,         9-10, e.g., 10-11. Method 4, wherein the pyrophosphate salt is         tetrasodium pyrophosphate and the composition has a pH from 5-9,         e.g., 5-8, e.g., 5-7, e.g., 5-6, e.g., 6-8, e.g., 6-7, e.g.,         8-9.     -   4.2 Method 4, wherein the complex is formed in situ in an         aqueous solution and combined with the oral care base, e.g.,         wherein the aqueous solution has a pH from 5-11, e.g., 5-10,         e.g., 5-9, e.g., 5-8, e.g., 5-7, e.g., 5-6, e.g., 6-8, e.g.,         6-7, e.g., 8-9, e.g., 9-10, e.g., 10-11. Method 4, wherein the         pyrophosphate salt is tetrapotassium pyrophosphate and the         aqueous solution has a pH from 5-11, e.g., 5-10, e.g., 5-9,         e.g., 5-8, e.g., 5-7, e.g., 5-6, e.g., 6-8, e.g., 6-7, e.g.,         9-10, e.g., 10-11. Method 4, wherein the pyrophosphate salt is         tetrasodium pyrophosphate and the aqueous solution has a pH from         5-9, e.g., 5-8, e.g., 5-7, e.g., 5-6, e.g., 6-8, e.g., 6-7,         e.g., 8-9.     -   4.3 Method 4 or 4.2, wherein the complex is combined as a solid         with the oral care base, e.g., wherein the complex is isolated         from the aqueous solution in solid form and combined with the         oral care base, e.g., mouthwash, oral gel, or dentifrice base,         e.g., a mouthwash base.     -   4.4 Any of Method 4, 4.2, or 4.3, wherein the complex is         lyophilized and combined the complex with an oral care base,         e.g., mouthwash, oral gel, or dentifrice base, e.g., a mouthwash         base.     -   4.5 Any of the foregoing methods, wherein the complex is         isolated with an anti-solvent, e.g., an organic solvent, e.g.,         ethanol, and combined with the oral care base, e.g., mouthwash,         oral gel, or dentifrice base, e.g., a mouthwash base.     -   4.6 Any of the foregoing methods, wherein the complex is made as         described in any of Method 2 et seq.     -   4.7 Any of the foregoing methods, wherein the complex is present         in an amount of 2-30 weight % by weight of the composition     -   4.8 Any of the foregoing methods, wherein the complex is made by         mixing the tin (II) fluoride and pyrophosphate salt, e.g.,         alkali pyrophosphate salt, in a molar ratio of at least 1P:1Sn,         e.g., 1P:1Sn to 15P:1Sn, e.g., 1P:1Sn to less than 15P:1Sn,         e.g., 1P:1Sn to 10P:1Sn, e.g., 1P:1Sn to less than 10P:1Sn,         e.g., 1P:1Sn to 5P:1Sn, e.g., 1P:1Sn to less than 5P:1Sn, e.g.,         1P:1Sn to 2P:1Sn, e.g., 1P:1Sn, e.g., 2P:1Sn, e.g., 5P:1Sn,         e.g., 10P:1Sn, e.g., 15P:1Sn.     -   4.9 Any of the foregoing methods, wherein the complex is made by         mixing the tin (II) fluoride and pyrophosphate salt, e.g.,         alkali pyrophosphate salt, in a molar ratio of 1P:1Sn to         15P:1Sn, e.g., 1P:1Sn to 10P:1Sn, e.g., 1P:1Sn to less than         10P:1Sn, e.g., 1P:1Sn to 5P:1Sn, e.g., 1P:1Sn to 2P:1Sn, e.g.,         1P:1Sn, e.g., 2P:1Sn, e.g., 5P:1Sn, e.g., 10P:1Sn, e.g.,         15P:1Sn.     -   4.10 Any of the foregoing methods, wherein the complex is made         by mixing 1-10 weight % tin (II) fluoride by weight of the         mixture, e.g., 1-9 weight % tin (II) fluoride by weight of the         mixture, e.g., 2 weight % tin (II) fluoride by weight of the         mixture, and 1-10 weight % pyrophosphate salt, e.g., alkali         pyrophosphate salt, by weight of the mixture, e.g., 3-4 weight %         pyrophosphate salt, e.g., alkali pyrophosphate salt, by weight         of the mixture, e.g., 7-8 weight % pyrophosphate salt, e.g.,         alkali pyrophosphate salt, by weight of the mixture.     -   4.11 Any of the foregoing methods, wherein the pyrophosphate         salt is tetrapotassium pyrophosphate.     -   4.12 Method 4.11, wherein the complex is made by mixing the         tin (II) fluoride and tetrapotassium pyrophosphate salt in a         molar ratio of at least 1P:1Sn, e.g., 1P:1Sn to 15P:1Sn, e.g.,         1P:1Sn to less than 15P:1Sn, e.g., 1P:1Sn to 10P:1Sn, e.g.,         1P:1Sn to less than 10P:1Sn, e.g., 1P:1Sn to 5P:1Sn, e.g.,         1P:1Sn to less than 5P:1Sn, e.g., 1P:1Sn to 2P:1Sn, e.g.,         1P:1Sn, e.g., 2P:1Sn, e.g., 5P:1Sn, e.g., 10P:1Sn, e.g.,         15P:1Sn.     -   4.13 Method 4.11 or 4.12, wherein the complex is made by mixing         1-10 weight % tin (II) fluoride by weight of the mixture, e.g.,         1-9 weight % tin (II) fluoride by weight of the mixture, e.g., 2         weight % tin (II) fluoride by weight of the mixture, and 1-40         weight % tetrapotassium pyrophosphate by weight of the mixture,         e.g., 1-30 weight % tetrapotassium pyrophosphate by weight of         the mixture, e.g., 1-20 weight % tetrapotassium pyrophosphate by         weight of the mixture, e.g., 1-10 weight % tetrapotassium         pyrophosphate by weight of the mixture.     -   4.14 Any of Method 4 or 4.1-4.10, wherein the pyrophosphate salt         is tetrasodium pyrophosphate.     -   4.15 Method 4.14, wherein the complex is made by mixing the         tin (II) fluoride and tetrasodium pyrophosphate salt in a molar         ratio of 1P:1Sn to 10P:1Sn, e.g., 1P:1Sn to less than 10P:1Sn,         e.g., 1P:1Sn to 5P:1Sn, e.g., 1P:1Sn to less than 5P:1Sn, e.g.,         1P:1Sn to 2P:1Sn, e.g., 1P:1Sn, e.g., 2P:1Sn, e.g., 5P:1Sn.     -   4.16 Method 4.14 or 4.15, wherein the complex is made by mixing         1-10 weight % tin (II) fluoride by weight of the mixture, e.g.,         1-9 weight % tin (II) fluoride by weight of the mixture, e.g., 2         weight % tin (II) fluoride by weight of the mixture, and 1-30         weight % tetrasodium pyrophosphate by weight of the mixture,         e.g., 1-20 weight % tetrasodium pyrophosphate by weight of the         mixture, e.g., 1-10 weight % tetrasodium pyrophosphate by weight         of the mixture.     -   4.17 Any of the foregoing methods, wherein the oral care base is         a mouthwash base.

Tin (II) fluoride and a pyrophosphate salt, e.g., an alkali pyrophosphate salt, e.g., tetrapotassium pyrophosphate (K₄P₂O₇) (TKPP) or tetrasodium pyrophosphate (Na₄P₂O₇) (TSPP), may be combined to form a pre-formed aqueous soluble tin phosphate complex, e.g., any of Complex 1 et seq., which may be prepared in bulk, and then incorporated into the oral care compositions disclosed herein, e.g., any of Composition 1 et seq. Alternatively, tin (II) fluoride and a pyrophosphate salt, e.g., tetrapotassium pyrophosphate (K₄P₂O₇) (TKPP) or tetrasodium pyrophosphate (Na₄P₂O₇) (TSPP), may be combined during the manufacture of the oral care compositions disclosed herein, e.g., any of Composition 1 et seq., to form the complex in situ in the composition.

In some embodiments the oral care compositions disclosed herein, e.g., any of Composition 1 et seq., comprise one or more further fluoride ion sources—i.e., a fluoride-containing compound having a beneficial effect on the care and hygiene of the oral cavity, for example, diminution of enamel solubility in acid and protection of the teeth against decay. Any suitable fluoride source may be employed including, without limitation, sodium fluoride, stannous fluoride, potassium fluoride, potassium stannous fluoride (SNFZ-KF), potassium fluorozirconate, sodium hexafluorostannate, stannous chlorofluoride, sodium monofluorophosphate (MFP), or a combination of two or more thereof. Where present, the fluoride source may provide fluoride ion in amounts sufficient to supply 25-25,000 ppm of fluoride ions, generally at least 500 ppm, e.g., 500-2000 ppm, e.g., 1000-1600 ppm, e.g., 1450 ppm. The appropriate level of fluoride will depend on the particular application. A toothpaste for general consumer use would typically have 1000-1500 ppm, e.g., 1100 ppm, e.g., 1000 ppm, with pediatric toothpaste having somewhat less. A dentifrice or coating for professional application could have as much as 5,000 or even 25,000 ppm fluoride. In some embodiments, the one or more further fluoride ion sources are present in the oral care compositions disclosed herein, e.g., Composition 1 et seq., in an amount of 0.01-5 weight % by weight of the composition, e.g., 0.01-2 weight % by weight of the composition, e.g., 0.01-1 weight % by weight of the composition.

In some embodiments, the oral care compositions disclosed herein, e.g., any of Composition 1 et seq., comprise one or more humectants. Any suitable humectant may be employed including, without limitation, polyhydric alcohols (polyols) such as propylene glycol, glycerin, sorbitol, xylitol, low molecular weight polyethylene glycols (PEGs), or a combination of two or more thereof. Humectants may, for example, prevent hardening of paste or gel compositions upon exposure to air. Certain humectants may also impart desirable sweetness of flavor to the compositions. In some embodiments, the one or more humectants are present in the oral care compositions disclosed herein, e.g., any of Composition 1 et seq., in an amount of 2-50 weight % by weight of the composition, e.g., 10-40 weight % by weight of the composition, e.g., 15-30 weight % by weight of the composition.

In some embodiments, the oral care compositions disclosed herein, e.g., any of Composition 1 et seq., comprise one or more surfactants. Any suitable surfactant may be employed including, without limitation, anionic, nonionic, and amphoteric surfactants. Surfactants may, for example, provide enhanced stability of the composition, to help in cleaning the oral cavity surfaces through detergency, and to increase foaming of the composition upon agitation, e.g., during brushing. Suitable anionic surfactants include, for example, water-soluble salts of C₈₋₂₀ alkyl sulfates, sulfonated monoglycerides of C₈₋₂₀ fatty acids, sarcosinates, taurates, or a combination of two or more thereof; for example sodium lauryl sulfate, sodium coconut monoglyceride sulfonate, sodium lauroyl sarcosinate, sodium lauroyl isoethionate, sodium laureth carboxylate, sodium dodecyl benzenesulfonate, or a combination of two or more thereof. In some embodiments, the one or more surfactants are present in the oral care compositions disclosed herein, e.g., Composition 1 et seq., in an amount of 1-10 weight % by weight of the composition.

In some embodiments, the oral care compositions disclosed herein, e.g., any of Composition 1 et seq., comprise one or more thickeners, which may impart a desired consistency and/or mouth feel to the composition. Any suitable thickener or binder may be employed including, without limitation, carbomers (also known as carboxyvinyl polymers), carrageenans (also known as Irish moss and more particularly 1-carrageenan (iota-carrageenan)), cellulosic polymers such as hydroxyethylcellulose, carboxymethylcellulose (CMC) and salts thereof, e.g., sodium CMC, natural gums such as gum karaya, xanthan gum, gum arabic, and gum tragacanth, inorganic thickeners such as colloidal magnesium aluminum silicate, colloidal silica, and the like, or a combination of two or more thereof. In some embodiments, the one or more thickeners are present in the oral care compositions disclosed herein, e.g., Composition 1 et seq., in an amount of 1-10 weight % by weight of the composition.

In some embodiments, the oral care compositions disclosed herein, e.g., any of Composition 1 et seq., comprise one or more flavorings. Any suitable flavoring, e.g., sweetening agent, may be employed including, without limitation, flavoring oils (e.g. oil of spearmint, peppermint, wintergreen, clove, sage, eucalyptus, marjoram, cinnamon, lemon, and orange), sucrose, sucralose, lactose, maltose, xylitol, stevia, sodium cyclamate, perillartine, aspartame, liquorice, saccharin or a salt thereof, or a combination of two or more thereof. In some embodiments, the one or more flavorings are present in the oral care compositions disclosed herein, e.g., any of Composition 1 et seq., in an amount of 0.01-10 weight % by weight of the composition, e.g., 0.05-5 weight % by weight of the composition, e.g., 0.05-0.2 weight % by weight of the composition, e.g., 1-3 weight % by weight of the composition.

In some embodiments, the oral care compositions disclosed herein, e.g., any of Composition 1 et seq., comprise one or more colorants. Any suitable colorant may be employed including, without limitation, zinc oxide, talc, titanium dioxide, pigments, dyes, or a combination of two or more thereof. In some embodiments, the colorant is a water soluble oral grade dye or colorant, including naturally-derived dyes (e.g., chlorophyll). In some embodiments, the oral care compositions disclosed herein, e.g., any of Composition 1 et seq., comprise the one or more colorants, in an amount of 0.01-5 weight % by weight of the composition, e.g., 0.05-2 weight % by weight of the composition.

In some embodiments, the oral care compositions disclosed herein, e.g., any of Composition 1 et seq., comprise water. Water employed in the preparation of commercial oral care compositions should be deionized and free of organic impurities. In some embodiments, water makes up the balance of the oral care compositions. In some embodiments, the oral care compositions disclosed herein, e.g., any of Composition 1 et seq., comprise water in an amount of 2-90 weight % by weight of the composition, e.g., 2-50 weight % by weight of the composition, e.g., 50-80 weight % by weight of the composition.

A complex disclosed herein may be described by reference to a spectrum as “substantially” shown or depicted in a figure or by one or more data points. It will be appreciated that a Fourier transform infrared, Raman, or NMR spectrum of a given sample may vary depending on factors known to those of skill in the art, e.g., instrument used, etc. Therefore, the Fourier transform infrared, Raman, and NMR spectrum peaks set forth herein will have an acceptable level of deviation. For example, for Fourier transform infrared spectra, the peaks may have an acceptable deviation of e.g., ±20 cm⁻¹ or ±16 cm⁻¹ or ±4 cm⁻¹ or ±2 cm⁻¹ or ±1 cm⁻¹ or ±0.5 cm⁻¹. For example, for Raman spectra, the peaks may have an acceptable deviation of, e.g., ±1-2 cm⁻¹, e.g., ±1 cm⁻¹, e.g., ±2 cm⁻¹. For example, for NMR spectra, the peaks may have an acceptable deviation of, e.g., ±1 ppm.

As used herein, “aqueous solution” means a solution in which the solvent is water.

As used herein, “aqueous soluble tin phosphate complex” includes a complex in which 1 gram of the complex is soluble in 1 or 10 to 100 ml water, e.g., 1 or 10 to 90 ml water, e.g., 1 or 10 to 80 ml water, e.g., 1 or 10 to 70 ml water, e.g., 1 or 10 to 60 ml water, e.g., 1 or 10 to 50 ml water, e.g., 1 or 10 to 40 ml water, e.g., 1 or 10 to 30 ml water, e.g., 1 or 10 to 20 ml water, e.g., 1-10 ml water, e.g., less than 1 ml water.

EXAMPLES Example 1

TABLE 1 Stannous Fluoride Stock Solution Preparation % SnF₂ SnF₂ (g) Total (g) 20 4 20

TABLE 2 Tetrasodium Pyrophosphate (TSPP) Solution Preparation P:Sn Molar Ratio TSPP (g) SnF₂ Sol (g) Total (g) pH 0.5 0.08 1 10 1 0.2 1 10 5.5 2 0.3 1 10 6.6 5 0.8 1 10 8.8 10 1.7 1 10

TABLE 3 Tetrapotassium Pyrophosphate (TKPP) Solution Preparation P:Sn Molar Ratio TKPP (g) SnF₂ Sol (g) Total (g) pH 0.5 0.1 1 10 1 0.2 1 10 5.6 2 0.4 1 10 6.8 5 1.1 1 10 9.3 10 2.1 1 10 10.0 15 3.2 1 10 10.4

The solutions are prepared by first dissolving TSPP or TKPP in water (mixing under high heat if necessary) and then adding a 20% stannous fluoride solution to the clear solution with an automatic pipet. The pH of all clear solutions is recorded. All of the solutions contain 2% SnF₂.

With TSPP, clear solutions are observed for solutions with P/Sn molar ratios of 1, 2, and 5. At molar ratios 10 and greater, TSPP does not fully dissolve.

With TKPP, clear solutions are observed for all tested P/Sn molar ratios greater than or equal to 1. TKPP is more water soluble than TSPP.

Solutions are aged overnight at room temperature. A 2% stannous fluoride solution is used as a control, which shows precipitate almost immediately after dissolution. After overnight aging, TSPP solutions with a P/Sn molar ratio spanning from 1 to 5 remain clear. After overnight aging, TKPP solutions with a P/Sn molar ratio spanning from 1 to 15 remain clear.

All stable solutions remain stable after 4 weeks of aging at room temperature.

Example 2

TABLE 4 Preparation of 1% Bovine Serum Albumin (BSA) Solutions Amount of Sample Amount of BSA (g) Total Solution (g) TSPP 1Sn:1P solution 0.03 3 TSPP 1Sn:2P solution 0.03 3 TSPP 1Sn:5P solution 0.03 3 TKPP 1Sn:1P solution 0.03 3 TKPP 1Sn:2P solution 0.03 3 TKPP 1Sn:5P solution 0.03 3 TKPP 1Sn:10P solution 0.03 3 TKPP 1Sn:15P solution 0.03 3 Control: 1% BSA in DI water 0.03 3

Aging of the BSA Solutions

Bovine serum albumin (BSA) is used to model interaction of solutions with oral proteins.

Clear TSPP and TKPP solutions are aged at 37° C. overnight after the addition of 1% BSA.

All three solutions of SnF₂+TSPP (P/Sn molar ratios of 1, 2, and 5) with 1% BSA form a precipitate after aging overnight at 37° C.

Solutions of SnF₂+TKPP with P/Sn molar ratios of 1, 2, 5, and 10 with 1% BSA form a precipitate after aging overnight at 37° C. The solution with a P/Sn molar ratio of 15 fails to completely dissolve the BSA, and no change is observed overnight.

A 1% BSA control after aging overnight at room temperature shows no precipitate. A 1% BSA control after aging overnight at 37° C. shows no precipitate.

Bovine serum albumin (BSA) stimulates proteins found in saliva. Formation of precipitate upon exposure to BSA may block dentin tubules to provide hypersensitivity relief.

Example 3

A clear solution comprising 2% stannous fluoride (SnF₂) and tetrasodium pyrophosphate (TSPP) with a P:Sn molar ratio of 1 is lyophilized using a Labconco FreeZone 2.5 Freeze Dryer. FTIR-ATR analysis is conducted on freeze dried powder on an extended range Spectrum One Perkin Elmer system featuring a CsI beam splitter, DTGS detector, and single-bounce diamond KRS-5 ATR crystal. Sample is placed directly on the ATR diamond. See FIG. 1. Peaks observed for the Sn-TSPP complex are listed in Table 5 (broad peaks from water/ethanol at about 1640 and 3200 cm⁻¹ are omitted from peak table).

TABLE 5 Wavenumber Absorbance (cm⁻¹) (A) 481 0.6901 546 0.9997 722 0.3353 881 0.7443 979 0.4082 1081 0.5859 1101 0.5938

Ethanol is added dropwise to a clear solution comprising 2% stannous fluoride (SnF₂) and tetrasodium pyrophosphate (TSPP) with a P:Sn molar ratio of 1 until precipitate forms. Solid is filtered and air dried. FTIR-ATR analysis is conducted on solid on an extended range Spectrum One Perkin Elmer system featuring a CsI beam splitter, DTGS detector, and single-bounce diamond KRS-5 ATR crystal. Sample is placed directly on the ATR diamond. See FIG. 2. An FTIR-ATR for solid SnF₂ is in FIG. 5.

FTIR-ATR analysis may be conducted on about 10-100 mg of solid.

Example 4

Solutions of 2% SnF₂ and TSPP in water with P/Sn molar ratios of 1, 2, and 5 are prepared. The solutions are analyzed as-prepared on an Agiltron PeakSeeker Raman System equipped with a fiber optic probe designed for liquid samples. The spectra, obtained in 30 second integration times, is compared to that of scintillation vials containing deionized water as a blank using RSIQ software. Raman spectra for the solutions are shown in FIG. 6 and peaks are listed in Table 6 (below).

TABLE 6 Raman Shift Sample (cm⁻¹) P/Sn 1 None P/Sn 2 1022 P/Sn 5 1022

Example 5

A 2% SnF₂ solution with TSPP at a P:Sn molar ratio of 1 is prepared in a 50 mL centrifuge vial according to the following: 0.8 g SnF₂, 0.5 g TSPP, 40 g total (with H₂O). Vortex and sonicate until solution is clear. Roughly 32.5 mL is left in the centrifuge vial while the rest is transferred to a scintillation vial. To the 32.5 mL, 18 g 100% EtOH is added, yielding an opaque solution that settles a white precipitate to the bottom. The solution becomes opaque once >13.58 g EtOH is added. The sample is left overnight at room temperature. The solid is centrifuged, decanted, and washed with EtOH.

Elemental analysis of the solid is obtained providing a P:Sn:Na molar ratio. Fluoride is calculated based on charge neutrality (assuming Sn remains in +2 oxidation state). Prior to analysis, the solid is dissolved in nitric acid. Phosphorous is quantified via ICP-OES, while Na and Sn are quantified using AAS.

TABLE 7 Results: 1 pyrophosphate⁴⁻ (P₂O₇ ⁴⁻):1 Na⁺:2 Sn²⁺:1 F⁻ % mmol Mol Ratio Phosphorus 12.30 3.97 2 Sodium 4.64 2.02 1 Tin 47.54 4.00 2

Example 6

Solutions of 2% SnF₂ and TSPP in water with P/Sn molar ratios of 1, 2, and 5 are prepared. 5 weight % D₂O is added to the solutions. ³¹P and ¹¹⁹Sn NMR are acquired on a Bruker AVANCE 500 spectrometer working at 202.4 MHz for ³¹P NMR and 163.5 MHz for ¹¹⁹Sn NMR at room temperature. ³¹P NMR are externally referenced to 85% H₃PO₄ set to 0 ppm. ¹¹⁹Sn NMR are externally referenced to saturated SnF₂ in D₂O at −796 ppm prepared right before measurement. FIGS. 3, A, 3, B, and 3, C depict ³¹P NMR spectra of solutions with P:Sn molar ratios of 5 (FIG. 3, A), 2 (FIG. 3, B), and 1 (FIG. 3, C). FIGS. 4, A, 4, B, and 4, C depict ¹¹⁹Sn NMR spectra of solutions with P:Sn molar ratios of 5 (FIG. 4, A), 2 (FIG. 4, B), and 1 (FIG. 4, C). ³¹P NMR peaks are listed in Table 8 and ¹¹⁹Sn NMR peaks are listed in Table 9. A ³¹P NMR spectrum of a solution of TSPP in water with 5 weight % D₂O added and externally referenced to 85% H₃PO₄ set to 0 ppm is in FIG. 7.

TABLE 8 P/Sn Molar Ratio ³¹P Chemical Shift (ppm) SnF₂-TSPP 5 −6.30 −9.82 −10.23 (doublet) −10.31 (doublet) SnF₂-TSPP 2 −8.34 −9.78 −10.49 −10.69 −11.09 SnF₂-TSPP 1 2.10 2.22 −9.03 −9.31 −9.65 −9.74 −10.36 −11.22 −11.40 −12.77 −14.35

TABLE 9 P/Sn Molar Ratio ¹¹⁹Sn Chemical Shift (ppm) SnF₂-TSPP 5 −640.63 −686.58 −693.76 SnF₂-TSPP 2 −642.35 −678.79 −724.61 SnF₂-TSPP 1 −672.97 −686.36 −696.08 −705.84 −734.85 −742.85 −747.93 −754.99 −764.39 −766.74 −773.79 −804.84 −813.14 −821.45

Example 7

A toothpaste comprising the aqueous soluble tin phosphate complex as disclosed herein can be formulated as described in Table 10 below:

TABLE 10 Material Weight Percent Aqueous 2-30% soluble tin phosphate complex Water 2-50% Alkali 1-10%, e.g., 5% phosphate(s) pH Agent(s) 1-5%, e.g., 3% Abrasive(s) 10-30%, e.g., 20% Thickener(s) 1-5%, e.g., 3% Surfactant(s) 1-5%, e.g., 3% Humectant(s) 2-50% Flavoring(s) 1-5%, e.g., 3% Coloring(s) 0.1-2%, e.g., 1%

Example 8

A mouthwash comprising the aqueous soluble tin phosphate complex as disclosed herein can be formulated as described in Table 11 below:

TABLE 11 Material Weight Percent Aqueous 2-30% soluble tin phosphate complex Fluoride ion 0.01-1%, e.g., source(s) 0.05% Flavoring(s) 0.005-0.5%, e.g., 0.1-0.15% Humectant(s) 10-30%, e.g., 20% Surfactant(s) 0.1-1%, e.g., 0.4% Water 50-80%

Example 9

TABLE 12 Tetrasodium Pyrophosphate (TSPP) Solution Preparation Solution Preparation (TSPP in 3% SnCl₂•2H₂O) P:Sn Molar Ratio TSPP (g) SnCl₂•2H₂O (g) Total (g) 0.5 0.2 0.6 20 1 0.3 0.6 20 2 0.7 0.6 20 5 1.7 0.6 20 10 TSPP not soluble

Solutions are prepared by dissolving TSPP in deionized water (mixing under heat if necessary) and then adding 0.6 g of SnCl₂.2H₂O to make 20-gram solutions.

The solutions with a P/Sn molar ratio spanning from 0.5 to 5 containing 3% SnCl₂.2H₂O are aged overnight at room temperature. A 3% SnCl₂.2H₂O solution is used as a control. The control, 0.5:1, and 1:1 solutions each form a cloudy precipitate that settles after aging overnight. The 2:1 and 5:1 solutions form crystals immediately after the addition of SnCl₂.2H₂O. The crystals dissolve after aging for one week.

Example 10

TABLE 13 Tetraspotassium Pyrophosphate (TKPP) Solution Preparation Solution Preparation (TKPP in 3% SnCl₂•2H₂O) P:Sn Molar Ratio TKPP (g) SnCl₂•2H₂O (g) Total (g) 0.5 0.2 0.6 20 1 0.4 0.6 20 2 0.8 0.6 20 5 2.1 0.6 20 10 4.2 0.6 20 15 6.3 0.6 20

Solutions are prepared by dissolving TKPP in deionized water (mixing under heat if necessary) and then adding 0.6 g SnCl₂.2H₂O to make 20-g solutions.

The solutions with a P/Sn molar ratio spanning from 0.5 to 5 containing 3% SnCl₂.2H₂O are aged overnight at room temperature. A 3% SnCl₂.2H₂O solution is used as a control. The control, 0.5:1, and 1:1 solutions each form a cloudy precipitate that settles after aging overnight. The 2:1 solution forms a precipitate that settles immediately. The 5:1, 10:1, and 15:1 solutions are mostly clear with a small amount (decreasing as phosphate amount increases) of precipitate at the bottom of each vial. The amount of precipitate decreases after aging, but the precipitate never fully dissolves. 

What is claimed is:
 1. An oral care composition comprising an aqueous soluble tin phosphate complex formed from a mixture comprising tin (II) fluoride and a pyrophosphate salt.
 2. The composition of claim 1, wherein the complex is formed in situ in an aqueous solution and combined with the composition.
 3. The composition of claim 2, wherein the complex is isolated from the aqueous solution in solid form and combined with the composition.
 4. The composition of claim 1, wherein the complex is lyophilized and combined with the composition.
 5. The composition of claim 1, wherein the complex is isolated with an anti-solvent and combined with the composition.
 6. The composition of claim 1, wherein the complex is present in an amount of 2 to 30 weight % by weight of the composition.
 7. The composition of claim 1, wherein the complex is formed from a mixture comprising the tin (II) fluoride and pyrophosphate salt in a molar ratio of at least 1P:1Sn.
 8. The composition of claim 1, wherein the complex is formed from a mixture comprising the tin (II) fluoride and pyrophosphate salt in a molar ratio of 1P:1Sn to 15P:1Sn.
 9. The composition of claim 1, wherein the complex is formed from a mixture comprising 1 to 10 weight % tin (II) fluoride by weight of the mixture and 1 to 40 weight % pyrophosphate salt by weight of the mixture.
 10. The composition of claim 1, wherein the pyrophosphate salt is tetrapotassium pyrophosphate (K₄P₂O₇).
 11. The composition of claim 10, wherein the complex is formed from a mixture comprising the tin (II) fluoride and tetrapotassium pyrophosphate in a molar ratio of at least 1P:1Sn.
 12. The composition of claim 10, wherein the complex is formed from a mixture comprising the tin (II) fluoride and tetrapotassium pyrophosphate in a molar ratio of 1P:1Sn to 15P:1Sn.
 13. The composition of claim 10, wherein the complex is formed from a mixture comprising 1 to 10 weight % tin (II) fluoride by weight of the mixture and 1 to 40 weight % tetrapotassium pyrophosphate by weight of the mixture.
 14. The composition of claim 1, wherein the pyrophosphate salt is tetrasodium pyrophosphate (Na₄P₂O₇).
 15. The composition of claim 14, wherein the complex is formed from a mixture comprising the tin (II) fluoride and tetrasodium pyrophosphate in a molar ratio of 1P:1Sn to 5P:1Sn.
 16. The composition of claim 14, wherein the complex is formed from a mixture comprising 1 to 10 weight % tin (II) fluoride by weight of the mixture and 1 to 30 weight % tetrasodium pyrophosphate by weight of the mixture.
 17. The composition of claim 14, wherein the tin (II) fluoride and tetrasodium pyrophosphate (Na₄P₂O₇) form a complex having the formula [P₂O₇]⁴⁻Na⁺Sn²⁺ ₂F⁻.
 18. The composition of claim 1, wherein the composition comprises an aqueous solution.
 19. The composition of claim 1 further comprising more than 20 weight % water by weight of the composition.
 20. The composition of claim 1, wherein the composition is a mouthwash.
 21. The composition of claim 1 for use to reduce dentinal hypersensitivity.
 22. A method to reduce or inhibit dentinal hypersensitivity, dental caries, gingivitis, or plaque in a person in need thereof comprising applying an effective amount of an oral care composition as claimed in claim 1 to teeth of the person. 